Fires
Fires are produced as the result of three components: heat, fuel, and oxygen. Heat produces flammable gases as a result of the pyrolysis (thermal degradation) of polymer, resulting in the breakage of covalent bonds and the formation of a range of intermediate products. An adequate ratio between the flammable gases and oxygen results in the ignition of the polymer. The resulting combustion of the polymer leads to a production of heat that is spread out and fed back. This heat feedback sustains the combustion, resulting in flame spread.
Pyrolysis products that are initially produced as a result of a fire generally consist of a complex mixture of combustible and non-combustible gases, liquids (which may subsequently volatilize), solid carbonaceous chars and highly reactive species, such as free radicals (highly energetic hydrogen and/or hydroxy radicals that propagate the overall combustion process).
Fires occur frequently throughout the world, often causing severe injuries or fatalities to human beings and animals. Each year, over three million fires leading to approximately 29,000 injuries and 4,500 deaths are reported in the United States alone.
In October of 2003, the largest wildfire outbreak in California history caused fires to rage completely out of control for about two weeks in locations within California, including Los Angeles, resulting in a two billion dollar disaster that claimed approximately 3,335 homes and 20 lives. Thousands of California residents were forced to evacuate their homes and relocate to shelters.
Real property (houses, commercial buildings, warehouses, barns and similar structures) and personal property (furniture, electronic devices, appliances, clothing, jewelry, pieces of art, livestock, crops and the like) that are damaged or destroyed by fires can be prohibitively expensive to repair or replace. Certain pieces of personal property, such as photographs, videotapes and pieces of jewelry, are often priceless and irreplaceable. The total annual costs resulting from property losses caused by fires in the United States has been estimated to be over one hundred billion dollars. Personal property losses occur primarily in residences, where furniture, wallcoverings and clothing fuel the fire. Large financial losses may also be incurred when commercial structures, such as office buildings and warehouses, burn. Fires can also produce significant financial losses when they occur in airplanes, trains, ships, buses and other motorized vehicles, where passengers and freight are generally confined, and have a limited means for egress.
Fires frequently cause buildings to collapse, thereby exposing occupants to a risk of severe injury or death from collapsed building materials and falling debris. Although both of the 110-story twin towers of the New York World Trade Center had survived powerful hurricane gusts, and one of them had also survived a bomb explosion in 1993 (creating a 22-foot wide, 5-story deep crater at its base), both of the twin towers collapsed after fires occurred in the buildings following the crash of airplanes into their sides on Sep. 11, 2001. Experts subsequently concluded that structural damage to the towers was caused predominantly by fires, and that this damage was apparently severe enough to overburden the lower sections of the buildings, causing them each to collapse. Thousands of people that had been in the twin towers on Sep. 11, 2001 lost their lives, or were severely injured, as a result of smoke inhalation, falling debris, burning or jumping from windows.
Smoke contains toxic gases, such as carbon monoxide. It is widely acknowledged that carbon monoxide, which incapacitates fire victims, is the most frequent cause of death in building-related fires. The remainder of the deaths in these fires are generally caused by burns and falling building structures.
Fires frequently spread rapidly across products that are present in buildings, such as draperies, rugs, carpeting, upholstery, furniture and other window, wall, floor and ceiling coverings, and produce dense, and often deadly, smoke. Growing concern over the problem of reducing the likelihood of substrates, such as foam in furniture and mattresses, from igniting has prompted the United States Consumer Product Safety Commission to draft proposals that would require these articles not to burn when contacted with an open flame.
Methods for enhancing the flame retardance of consumer goods have been developed to provide protection from fires, and to increase the available escape time from fires.
Flame Retardants
In most cases, organic materials that do not have any flame retardant properties decompose to volatile combustible products when they are exposed to heat and, thus, initiate or propagate fires.
Flame retardant agents can be added to products, such as clothing, to inhibit or suppress the combustion process. The principle effects of flame retardant agents are to inhibit the development of a fire, or to inhibit or delay the spread of fire over a burning material. In actual fires, flame retardant agents generally function to reduce: (a) the heat release rate of a material; (b) the rate of combustion, degradation and consumption of a material (fire extinction); and (c) smoke emission, and the evolution of toxic gases. As a result, flame retardant agents can significantly increase the available escape time before flashover or the development of an incapacitating atmosphere occurs and, thereby, reduce the exposure of human beings and animals to toxic gases and burning.
Flame retardants can act chemically (by reactions in either the gas or solid phase) and/or physically (by cooling, by formation of a protective layer or by dilution of a matrix), and at different times during the combustion process, to inhibit, interfere with and/or otherwise suppress one or more of the following stages of the combustion process in a manner that reduces flame spread over a material and/or the overall heat release: (a) heating; (b) decomposition; (c) ignition; (d) flame spread; and/or (e) smoke production.
Flame retardant compounds can be organic or inorganic compounds containing, for example, halogens, such as chlorine or bromine, phosphorous, alumina and/or antimony. The families of flame retardants include: (a) chlorinated flame retardants; (b) brominated flame retardants; (c) phosphorous based flame retardants; (d) metal hydroxides; (e) melamine based flame retardants; (f) zinc borate; (g) low melting glasses; and (h) silicon-based materials.
Flame Resistance for Fabrics and Textiles
The ability of fabrics, textiles and clothing to retard flame is a highly desirable characteristic to which considerable attention has been directed for public safety. The United States Federal Trade Commission is currently setting standards that require flame retardant fabrics for many end uses of apparel.
Methods are available for developing various types of flame retardant fibers and fabrics. However, these methods generally possess a variety of disadvantages, the principal disadvantage being that the methods are not very durable, particularly to home or industrial launderings or cleaning processes. Fibers and fabrics treated in accordance with these methods generally have an inability to retain flame retardant properties that have been added thereto, or enhanced, after one or more washings, launderings or dry cleaning operations. The added flame retardant properties (and flame retardant agents providing such properties) are generally rendered ineffective, or significantly less effective, as a result of such washings, launderings or dry cleaning operations. Another disadvantage of these methods is that they often result in a waste of large quantities of flame retardant agents, other process components and water, causing these methods to be expensive and potentially detrimental to the environment when they are disposed. The poor recovery rates of process chemicals and solvents employed in flame retarding processes, most of which are lost to municipal waste treatment facilities, as well as required secondary washing process steps, introduce economic, process control and environmental disadvantages to such operations.
Many of the woven and non-woven thermoplastic and non-thermoplastic fibers, fibrous compositions and fabrics that are commonly used today in connection with mattresses, furniture upholstery, insulation and construction materials, and in other commercial, industrial or residential applications, burn when contacted with an open or other flame, sometimes producing toxic gases as a by-product. When treated with a flame retardant composition, thermoplastic fibers, fibrous compositions or fabrics may not burn, but may still melt, producing a molten plastic that can cause deep skin burns. It is this melting of, for example, covering materials, such as the outer surfaces of mattresses, that may allow an open flame to come into contact with other materials, such as non-woven interior construction materials, that the covering materials are supposed to protect, and that may not have been treated with a flame retardant agent.
Another problem associated with non-thermoplastic fibers, fibrous compositions and fabrics is that many non-woven or woven substrate manufacturers do not have the necessary equipment or expertise to add flame retardant agents to these fibers, fibrous compositions and fabrics in their production processes. Increased costs to these manufacturers, thus, may be incurred when roll or other goods or parts need to be shipped elsewhere for flame retarding treatment.
Environmental Impacts of Clothing Manufacture
Several pollution issues currently exist in connection with the manufacture of fabrics, textiles and clothing. As a result, the manufacture of such products often causes one or more of a variety of negative impacts upon the environment. For example, 25% of the insecticides used globally are placed upon cotton plants, which grown cotton to produce the world's most popular fabric. Additionally, many synthetic fabrics, such as polyester, are manufactured from petroleum products that are not biodegradable. Further, many fiber or fabric finishing processes, such as a wide variety of dyeing processes, are highly toxic and polluting to the environment and, thus, are not “environmentally friendly” processes.
Description of the Art
U.S. Pat. No. 4,600,606 (“the '606 patent”) describes a process for rendering non-thermoplastic fibers and fibrous compositions flame resistant when contacted with a hot molten material (to prevent severe burns and blisters to workers and others that are exposed to hot molten metals, glass or other materials). The process involves the application to the fibers and fibrous compositions of a flame retardant composition incorporating a water-insoluble, non-phosphorous solid, particulate mixture of brominated organic compound and either: (a) a metal oxide of the formula Me2On (wherein Me is aluminum, silicon, arsenic, bismuth, titanium, zirconium, molybdenum, tin or antimony, and n is the valence of the metal), such as antimony oxide (Sb2O3), in a water insoluble, particulate form (having an average size not exceeding about 20 microns); or (b) a metal oxide as described in (a) and a metal hydrate, such as a mixture of antimony oxide and alumina trihydrate. After materials are treated with the compositions described in the '606 patent, and excess composition is removed, the wet material is cured by a two-step process: (a) drying the material at a temperature between 80° C. and 130° C.; and (b) then, in a separate step, baking the material at a temperature between 140° C. and 180° C. for ½ to 5 minutes.
In contrast with the compositions of the invention, which need not contain a metal oxide in order to be effective, and which can contain phosphorous-containing and other non-brominated flame retardant substances, the compositions described in the '606 patent contain a metal oxide and only contain non-phosphorous flame retardant substances. Additionally, the '606 patent does not teach or suggest flame retardant compositions that do not contain an amount of a dye, or of any other chemical compound, substance, agent or composition, that could have the effect of contaminating the flame retardant compositions, fibers or fibrous compositions described therein. Further, in contrast with the processes and systems of the invention, which do not require a curing step or a separate baking step after the drying step, or the heating equipment or energy resources associated with such curing and baking steps, the process described in the '606 patent requires a curing process that includes both a drying step and a separate baking step. Still further, the process described in the '606 patent does not teach or suggest the use of a “closed loop” process or system for applying flame retardant compositions to substrates, or the recycling of flame retardant compositions and/or rinse liquids.
U.S. Pat. No. 5,224,966 (“the '966 patent”) describes a process for the simultaneous dyeing and flameproofing of textile sheet materials made of polyester fibers using thermosol dyes. This patent also describes dye preparations that contain one or more disperse dyes in an amount of from 0.6 to 30 g/kg and one or more flame retardants in an amount of from 100 to 200 g/L, and that are employed to achieve different depths of shade. In contrast with the processes, systems and compositions of the present invention, the '966 patent does not teach or suggest: (a) the use of a flame retardant composition that does not contain an amount of a dye, or of any other chemical compound, substance, agent or composition, that could have the effect of contaminating the flame retardant compositions; (b) the use of an adhesion agent (or any weight percent thereof); (c) the use of a flame retardant substance in a particulate form (or having the size ranges described herein); (d) the reuse of a flame retardant composition that has been applied to one or more substrates; or (e) the use of a “closed loop” process or system in which flame retardant compositions and/or rinse liquids can be recycled.
U.S. Pat. No. 5,912,196 (“the '196 patent”) describes a flame retardant composition for treating high pulp content non-woven web that includes soluble solids formed from inorganic salts, such as ammonium polyphosphate, and sulfur. The '196 patent does not teach or suggest the use of a “closed loop” process or system for applying flame retardant compositions to substrates or the recycling of flame retardant compositions and/or rinse liquids, and does not discuss the durability of treated substrates or latexes.
U.S. Pat. No. 6,042,639 (“the '639 patent”) describes a method for impregnating combustible materials, such as wood, paper and textiles, with an aqueous fire retarding and smoke inhibiting composition. The composition comprises an aqueous solution of the reaction product of: (a) 0.5–90% by weight of an ammonium phosphate selected from monoammonium phosphate, diammonium phosphate and mixtures thereof; (b) 0.1–30% water soluble metal salts capable of forming water insoluble phosphate and ammonium phosphate salts; (c) 1–20% by weight acid, such as phosphoric acid; (d) 1–15% by weight dicyandiamide; and (e) up to 5% by weight additives, such as fungicides. Phosphoric acid and dicyandiamide are present in the composition in the form of the reaction product guanylureaphosphate. The method comprises impregnating a combustible material with the aqueous composition and drying the impregnated material to form fire retarding and smoke inhibiting characteristics in the material. In contrast with the processes, systems and compositions of the present invention, the '639 patent does not teach or suggest: (a) the use of an adhesion agent (or any weight percent thereof); (b) the use of a flame retardant substance in a particulate form (or having the size ranges described herein); (c) the reuse of a flame retardant composition that has been applied to one or more substrates; or (d) the use of a “closed loop” process or system in which flame retardant compositions and/or rinse liquids can be recycled.
Other patents or patent applications that describe inventions that are different from the compositions, processes, systems and/or substrates of the present invention include: (a) U.S. Pat. No. 1,339,488 (which describes a method for fire proofing fibrous materials using a solution containing preferably 6% or over of soluble borate to which a proportion of an alkali, such as potassium carbonate, has been added); (b) U.S. Pat. No. 4,756,839 (which describes an aqueous solution for projection (by spraying, pumping, etc.) onto an existing fire that includes potassium carbonate, a boron-containing compound, a potassium salt of an organic acid having from 1 to 6 carbon atoms and water, and that is stated to be effective in extinguishing fires, for example, grease fires on cooking surfaces or coal fires); (c) U.S. Pat. No. 4,961,865 (which describes methods and compositions for inhibiting the combustion of wood and other cellulosic materials by impregnating the materials with the compositions); (d) Patent Application Publication Number U.S. 2003/0017565 A1 (which describes methods and compositions for treating a porous article, such as wood, to provide flame retarding, rust-preventing, organism-repellant and other properties thereto by performing enzymatic macromolecularization reactions in the article using an enzyme having a polyphenol oxidizing activity (obtained by the cultivation of a fungus) in an alkaline pH region); (e) European Patent Application Publication No. 0 285 721 (which describes a method for protecting wood against fungal growth and fire that comprises applying to the surface of the wood an aqueous solution of sodium carbonate and sodium borate); (f) International Patent Application Publication No. WO 02/06021 A2 (which describes compositions comprising a boron source composition, a melamine binder resin and a urea casein activator resin that are stated to protect wood products from attack by termites, fungi, fire and flame, and methods for using these compositions); and (g) International Patent Application Publication No. WO 00/00570 (which describes a method for flame proofing insulating materials made with renewable raw materials).
Needs in the Art and Objects of the Invention
A need currently exists for methods, systems and compositions that can effectively flame retard substrates containing from about 5 to about 100 weight percent of non-thermoplastic material, such as non-thermoplastic filaments, microfibers, fibers, fibrous compositions, threads, yarns, fabrics, textiles, materials, items of apparel, paper or tissue, or blends or products produced using any of the foregoing materials, in an “environmentally-friendly,” cost effective and durable manner. A need also exists for improving currently-available processes, systems and compositions for fire retarding non-thermoplastic substrates. There is also a need for substrates containing at least about 5 weight percent of non-thermoplastic material, such as non-thermoplastic fibers, to be effectively treated with flame retardant materials before a non-woven, woven or other production process.
Accordingly, it is an object of the present invention to provide compositions, processes and systems for providing one or more flame retardant properties to one or more substrates containing from about 5 to about 100 weight percent of non-thermoplastic material, such as non-thermoplastic filaments, microfibers, fibers, fibrous compositions, threads, yarns, fabrics, textiles, materials, items of apparel, papers or tissues, or blends or products produced using any of the foregoing materials, whether woven or non-woven, and whether natural or synthetic, in a manner that conserves flame retardant agents and other process chemicals and compositions, as well as solvents, and that is “environmentally friendly” and durable, before, during or after a woven, non-woven or other production process.
It is another object of the present invention to provide methods and systems for reducing or eliminating the burning of, and/or the amount and density of smoke (which generally contains toxic gases) produced by, one or more substrates containing at least about 5 weight percent of non-thermoplastic material that is exposed to an open or other flame or fire.
It is also an object of the present invention to provide one or more methods for the application of flame retardant substances to substrates containing at least about 5 weight percent of non-thermoplastic material, such as non-thermoplastic filaments, microfibers, fibers, fibrous compositions, threads, yarns or blends prior to being woven, knitted or otherwise formed into fabrics, textiles, materials, items of apparel or other products produced using the foregoing materials.
It is another object of the present invention to provide flame retardant compositions for use in flame barrier substrates (protective substrates) containing at least about 5 weight percent of non-thermoplastic material, such as non-thermoplastic fibrous compositions, fabrics or textiles employed as outer coverings for other substrates, materials or products, for example, the central foam or other portions of cushions, pillows or mattresses, that provide one or more flame retardant properties against an open or other flame by forming a charred protective layer (a char) on one or more surfaces of the protective substrates when exposed to, or contacted with, a flame.
It is another object of the present invention to extract and recycle used or spent flame retardant compositions, rinse liquids and/or other process components used in processes or systems for flame retarding substrates, thereby reducing or eliminating the waste or release into the environment of, or the costs associated with, flame retardant compositions, rinse liquids or other substances. Preferably, if a rinse liquid is employed in processes or systems within the invention, used flame retardant composition is transferred to one holding vessel and the rinse liquid is transferred to a separate holding vessel, so that both of the substances can be reused in one or more subsequent applications of the flame retardant compositions and/or rinse liquids to substrates. Because neither the flame retardant compositions nor the rinse liquids employed in the processes and systems of the invention generally contain an amount of any dye or other substance that could contaminate the processes or systems (and preferably contain no dyes or other substances that could contaminate the processes or systems), the processes and systems of the invention can be performed in a “closed loop” manner, rather than in an “open loop” manner. Such “closed loop” processes and systems advantageously recycle, and thereby, conserve flame retardant and other process chemicals and rinse liquids, which are often expensive, as well as water or other solvents, thereby significantly reducing costs that are generally otherwise associated with the flame retarding of substrates. These “closed loop” processes and systems also generally reduce or eliminate pollution to the environment, the requirement for pre-disposal processing of chemicals and liquids and the payment of waste disposal fees, and may generally be employed without the need for elaborate safety precautions.
The present invention provides processes, systems and compositions for effectively flame retarding substrates containing from about 5 to about 100 weight percent of non-thermoplastic material, such as those described above, in an “environmentally-friendly,” cost effective and durable (or non-durable) manner prior to, during or after a woven, non-woven or other production process, without wasting large quantities of flame retardant chemical compounds or compositions, solvents or rinse liquids. Within the same processes or systems of the invention, both unused and recycled flame retardant composition can be separately employed to provide one or more flame retardant properties to one or more substrates, or to enhance the flame retardant properties of one or more substrates, whether the substrates being treated are the same or different, or are of the same or a different type. As a result of the recycling (reuse) of flame retardant composition in these processes and systems, it is generally possible to reduce the costs of the components employed in the flame retardant compositions, such as flame retardant chemicals, by at least about 75%, and often by at least about 90% (and possibly higher).
The present invention provides flame retardant compositions that, when applied to the surfaces, or other areas or components, of substrates containing at least about 5 weight percent of non-thermoplastic material, such as filaments, microfibers, fibers, fibrous compositions, threads, yarns, fabrics, textiles, materials, items of apparel, paper or tissue, or blends or products produced using the foregoing materials, prior to an exposure to an open or other flame or fire, or when added to, or mixed with, these substrates during their manufacture or other production, advantageously provide a flame retardant finish or coating to the substrates that reduces the amount of burning that occurs to the substrates, and/or the amount or density of smoke (and associated toxic gases) produced by the substrates, when they are exposed to and open or other flame or fire. These substrates may advantageously be blended with one or more other substrates that do not have any flame retardant properties to produce a homogeneously blended product containing at least some substrates that have been treated in accordance with the compositions, methods or systems of the invention uniformly throughout the blended product, such as a blended fabric containing treated and untreated fibers.
Thus, the processes, systems, compositions and substrates of the present invention should reduce or prevent injury or death to human beings and animals, and destruction to real and personal property, resulting from fires, particularly when the substrates are employed as flame barrier substrates with other materials that do not have any flame retarding properties.
The above and other objects and advantages of the compositions, methods and systems of the current invention should become apparent by way of examples, and otherwise, from the more detailed descriptions of the preferred embodiments of the invention described herein.